Sugars should make up no more than 3% of total energy intake in the diet to reduce the significant financial and social burdens of tooth decay, finds new research from University College London and the London School of Hygiene and Tropical Medicine. Published in the open-access journal BMC Public Health, the study analyzed the effect of sugars on dental caries. It shows that sugars are the only cause of tooth decay in children and adults.

Free sugars are defined by the World Health Organization (WHO) Nutrition Guidance Advisory Group as follows: “Free sugars include monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, and sugars naturally present in honey, syrups, fruit juices, and fruit concentrates.” Tooth decay is the most common noncommunicable disease in the world, affecting 60% to 90% of school-age children and the vast majority of adults. In the United States, 92% of adults aged 20 to 64 years have experienced decay in at least one of their permanent teeth. The treatment of dental diseases costs 5% to 10% of total health expenditure in industrialized countries. Researchers used public health records from countries across the world to compare dental health and diet over time across large populations of adults and children. It was found that the incidence of tooth decay was much higher in adults than children, and increased dramatically with any sugar consumption above 0% of energy. Even in chidren, an increase from near-zero sugar to 5% of energy doubles the prevalence of decay and continues to rise as sugar intake increases. Current guidelines from the WHO set a maximum of 10% of total energy intake from free sugars, with 5% as a target. This equates to about 50 g of free sugars per day as the maximum, with 25 g as the target. The latest research suggests that 5% should be the absolute maximum with a target of less than 3%. To address tooth decay, the authors recommend a few radical policy changes to reduce sugar consumption, such as limiting free sugars in foods, and implementing a “sugars tax” to increase the cost of sugar-rich food and drinks.